The present invention is directed to the separation of oleophilic-hydrophobic material such as oil, grease, metal chippings, dirt, and the like from wash water.
Industrial machines contain metal parts that move "against" one another, as for example, gears, drive chains, bearings, etc. To aid the movement of these machine parts and to extend their useful life, lubricants such as oils and greases are oftentimes utilized. However, over a period of time, lubricants begin to lose their effectiveness due to the accumulation of dirt and dust, as well as from the severe conditions of heat, pressure, and friction, to which the lubricants are oftentimes subjected. Additionally, the metal machine parts suffer from wear despite the presence of such lubricants. As the metal parts wear, metal chippings become dispersed throughout the lubricant further soiling and detracting from the useful life of the lubricant. To assure that the machinery operates at an optimum level, the soiled lubricant must eventually be removed and replaced.
One such method of removing the soiled lubricant from industrial machinery is by cleaning the machinery with an aqueous cleaning composition containing a mixture of surfactant and enzyme. The waste-product of this cleaning procedure (i.e. the wash water) contains the soiled lubricant which consists of oil, grease, dirt, metal chippings, and the like, dispersed throughout the aqueous cleaning composition.
According to prior practice, this wash water was disposed of by simply dumping it into the local sewer system. However, local ordinances requiring a reduction in the volume of grease, oil and insoluble solids discharged into municipal sewers are becoming both more stringent and prevalent. Accordingly, it may not be possible to dispose of the wash water in the local sewer system. A potential alternative to disposing the wash water in the local sewer system is to use a waste hauling service. However, where relatively large volumes of wash water are generated, it can become prohibitively expensive to have it hauled away. Ideally, and in accordance with contemporary industrial practice, it would be particularly advantageous if the wash water could be treated so that its oil and water components could be recycled. Accordingly, there is presently a need for a method of treating wash water such that it is recyclable, or in the alternative, more easily and less expensively disposed of.